drm/vmwgfx: Remove unnecessary NULL checks before kvfree()

Since kvfree() already checks if its argument is NULL, an additional
check before calling kvfree() is unnecessary and can be removed.

Remove both and the following Coccinelle/coccicheck warnings reported by
ifnullfree.cocci:

  WARNING: NULL check before some freeing functions is not needed
  WARNING: NULL check before some freeing functions is not needed
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241007115131.1811-3-thorsten.blum@linux.dev

drivers/gpu/drm/vmwgfx/vmwgfx_blit.c

@@ -635,9 +635,7 @@ int vmw_bo_cpu_blit(struct vmw_bo *vmw_dst,
 		kunmap_atomic(d.src_addr);
 	if (d.dst_addr)
 		kunmap_atomic(d.dst_addr);
-	if (src_pages)
 	kvfree(src_pages);
-	if (dst_pages)
 	kvfree(dst_pages);
 
 	return ret;